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PATENTED Nov 2e 1867 W/TNESSES @einen tutrs getraut @frn 'rf s. SMITH,CE NEW HAVEN, CONNECTICUT. Letters .Patent No. 71,546, dated November26, 136;?.

IMPROVED BALL GASTER.

TO ALL WHOM IT MAY CONCERN.:

Be it known that I, T. S. SMITH, of New Haven, in the county of NewHaven, and State of Connecticut, i have invented a new Improvement inBall Casters; and I do hereby declare the following, when taken inconnection with theV accompanying drawings, and the letters of referencemarked thereon, to be a full, clear, and exact description of the same,and which said-drawings constitute part of this specification, andrepresent, in

Figure 1, a side view Figure 2 a. central section, and in Figure 3 anunder side view of the ball-seat. l This invention relates to animprovement in casters for furniture, and consists in the peculiarformation of the seat combined with the hall, whereby the driving-pointis far above the centre, and near the point of bearing.

Bull casters of various forms have been constructed, but generally sogreat has 'heen the friction, that when attached to heavy articles thehall would not revolve, but in all such, the point of driving the ball,that is, the point which bears against the ball in the movement of thefurniture, is so far below the centre and distant from the point ofbearing, that thc leverage from the point of bearing to the point ofdriving and point of contact with the floor is so great' that the ballwill not revolve.

' By my invention these diiiculties are entirely overcome, and in orderto the better understanding of my l invention, as well as to enableothers to construct the same, I will proceed to n description thereof.As illustrated in the accompanying drawings-- A is tue upper part orseat of the caster, formed with a recess, B,hav,ing straight sides, asseen in fig. 3. These may he three or four; I prefer four. The bottom ofthis recess is flat, so that the ball C will bear against thc surface ofthe recess with the least possible friction, and when so hearing, thesides of the recess are of such dimensions that, when bearing upon oneside, the hall will'not quite touch the opposite side. Thus, when theseat A is fixed to'the furniture, and the rball C placed in the recessthereunder, the weight is supported upon the ball upon a. single point,and when` the furniture is moved, say to the left, the point a of oneside of" the recess hears against the ball near the top, so that theleverage from the ordinary construction is reversed, and the longer armof the lever being4 toward the floor, upon whichtis the greater amountof friction, and thus the ball will be driven, revolving upon the pointof Contact upon the surface of the recessB. In order to prevent the ballfrom dropping from its seat, when the furniture is raised, I form a cup,D, which wholly or partially surrounds the ball belbw its centre, butsous not to touch the ball when the weight of the furniture rests uponvthe ball. This cup is attached to` the sont in any convenient manner, sothat, when the furniture is raised, the ball will drop into the cup, andbe held in position-to return to its seat when the furniture is againset down. v

I Clonot broadly claim a ball caster, as such are common und well known;but What I do claim as new and useful, und desire to secure hy LettersPatent, is- The seat A, constructed with n recess, B, so as to form anangular recess, said recess forming a single bearing-point on the top,and two driving-points a near the top of the ball, ns set forth.

, VT. S. SMITH. Witnesses: I JOHN E. EAnLE,

A. J. Trnnus.

